Kerry says such discussions are "irrational" at a time when Russian and Syrian warplanes are bombing Aleppo. He says the US has no indication of Russia's "seriousness of purpose."
The US has been working with Russia for months to try to secure a cease-fire in Syria. The latest truce collapsed last week after several days of relative calm.
Speaking today at the Atlantic Council, Kerry outlined no new approaches for bringing peace to Syria. The administration has made clear it won't use military force against Syria's government.